Objective: To investigate the effects of short rest intervals normally associated with hypertrophy-type training versus long rest intervals traditionally used in strength type training on muscular adaptations in a cohort of young, experienced Lifters.

Background

Muscle hypertrophy and adaptations are maximized by manipulating resistance training variables including exercise, weight, form, number of reps, and time between sets to name a few, there are more.

If you’ve ever worked out for strength gains, you know that resting between sets is a big part of your workout. On one hand, you’d like to wait 5 minutes between sets to maximize rest, but on the other hand, you don’t wait to workout for 2 or 3 hours a day.

Prior studies have found no difference between 2 and 5 minutes; another study showed 2.5 minutes was better than 1 minute. Paradoxically, in another study of elderly men, 1 minute rest intervals were superior to 4 minute rest intervals.

Although longer rest periods are intuitively better, the jury is still out and the optimal rest time remains unclear. The authors of this study sought to build on this knowledge by comparing 1 and 3 minute rest intervals.

Methods

21 men performed resistance-training workouts with either

1-minute rest intervals (SHORT)

3-minute rest intervals (LONG)

All other variables were held constant.

The study period lasted 8 weeks with subjects performing 3 total body workouts a week comprised 3 sets of 8–12 repetition maximum (RM) of 7 different exercises per session.

Testing was performed before and after for muscle strength (1RM bench press and back squat), muscle endurance (50% 1RM bench press to failure), and muscle thickness of the elbow flexors, triceps brachii, and quadriceps femoris by ultrasound imaging.

Results

Maximal strength was significantly greater for both 1RM squat and bench press for long rest interval compared to short.

Muscle thickness was significantly greater for long rest interval compared to short in the anterior thigh, and a trend for greater increases was noted in the triceps brachii (p = 0.06) as well.

Both groups saw significant increases in local upper body muscle endurance with no significant differences noted between groups.

Conclusions

This study provides evidence that longer rest periods promote greater increases in muscle strength and hypertrophy in young resistance-trained men.

This isn’t really a surprise, right? 3 minutes of rest is better than 1 minute of rest. I think this provides us some ammunition for future research, where we can see if 2 minutes is equivalent to 3 minutes, is 4 minutes better than 3 minutes? These are the questions that need to be asked for optimal rest time between sets.